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PostPosted: February 23, 2015, 8:30 pm 
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Location: Lynchburg, VA
The project is to get the car to stand on it's two wheels and not topple over (okay, call it a bike if that makes you happier).

I had a sort-of decent design using the weight of the driver moving the seat (side-to-side), but I ended up having too little room. So instead I am looking for an instrument which will keep the balance; it seems pretty simple and it is. I need something that doesn't require driver input, which would be confusing, but creates a force to correct excess movement laterally.

The design has a pair of front wheels that stay on the road, and a single wheel in back which rotates side-to-side. The need is for a device to keep it centered according to apparent gravity; I have all the mechanisms for this, just need a sensitive lead to open and close hydraulic valves. Two valves, as I said, very simple.

Any ideas on where to search would be welcome.


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PostPosted: February 23, 2015, 8:46 pm 
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Adjustable pendulum.

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PostPosted: February 23, 2015, 9:05 pm 
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Thank you miataV8.

I will have to check carefully to see how much force it takes to move a hydraulic valve under maybe 1500 psi. If I can work out a balance there it will work. I appreciate your help.


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PostPosted: February 23, 2015, 9:22 pm 
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gyroscope?

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PostPosted: February 24, 2015, 6:41 am 
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Use a microswitch on each side of the pendulum, controlling a 12-14vdc solenoid valve. This can make it extremely sensitive and will allow the location of the hydraulic lines to be optimized as well as the pendulum.

Determine the desired rate with a manual test before ordering solenoids.

Specs:
http://www.eaton.com/ecm/groups/public/ ... l_2138.pdf

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PostPosted: February 24, 2015, 10:52 am 
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How about a pair of proportional electric brake controllers mounted laterally and face to face. Place springs on the wheel/axle to keep it centered with no control. As lateral force is applied, they would control their own valve to push the wheel to the side proportionally to the force applied.

I don't know if this is practical or in your cost range. Proportional controllers can be had for as low as $60 per.

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PostPosted: February 24, 2015, 4:12 pm 
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I need to know more about proportional controllers; right now I look inside my head and see nothing!

How big are they, how do they work, and so forth. Suggest a connection for me.

The solenoid valves look promising, as soon as I can get my head around the types and what is best for this application.


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PostPosted: February 24, 2015, 7:38 pm 
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It occurs to me that I need a variable speed; something that adds fluid at an increasing force/rate as the demand comes on.

If the car is cruising and needs little correctional bumps to keep it straight, as opposed to when it is under duress, pressed to perform quickly. I want something to do both jobs at once, or at least one-after-the-other without a lag.

That is why the person in the seat works best; he reacts to forces on the car and corrects them before they get outa hand. Now just add a synthetic helper to take off the pressure.


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PostPosted: February 25, 2015, 9:42 am 
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Seems like this might come in handy: accelerometer

I was looking at some ideas to do a locost semi-active suspension using the output from the left-right to power a linear actuator to "adjust" a swaybar. (I decided that the available (affordable) linear actuators might not react quick enough to be effective or, worse, be safe.)

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PostPosted: February 26, 2015, 12:21 pm 
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rapt wrote:
It occurs to me that I need a variable speed; something that adds fluid at an increasing force/rate as the demand comes on.

If the car is cruising and needs little correctional bumps to keep it straight, as opposed to when it is under duress, pressed to perform quickly. I want something to do both jobs at once, or at least one-after-the-other without a lag.

That is why the person in the seat works best; he reacts to forces on the car and corrects them before they get outa hand. Now just add a synthetic helper to take off the pressure.


That is why I would not do a side by side. If you were single seat, all you'd need are 4 pulleys, two bell crank foot pedals, another bellcrank underneath, two links, two cables, and two tension overload springs with tensioners.
Like GM's Lean Machine. At least I think that is how it works. I have not seen the system to know for sure.

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PostPosted: February 26, 2015, 1:04 pm 
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Quote:
It occurs to me that I need a variable speed; something that adds fluid at an increasing force/rate as the demand comes on.


That is essentially what the proportional (inertial) brake controller does, although in an electrical way, not hydraulic. The more inertial force applied, the higher the voltage output. If combined with a electrically controlled hydraulic valve, It may be possible to control the rate of flow thru that valve. If you can tune the system according to your needs, I do not know. But the basics are there.

Here is just one description of how these work: http://auto.howstuffworks.com/auto-part ... llers1.htm

Do not look at "timed" brake controllers as they will not work as you desire.

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“Any suspension will work if you don’t let it.” - Colin Chapman

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PostPosted: February 26, 2015, 7:38 pm 
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Here is my latest on paper, at least I think I can transmit the image (sketch).

In this pic there are some things left out, like what the inside of those 2 cylinders looks like. If I can get a similar valve, it should work.


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PostPosted: February 26, 2015, 7:45 pm 
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I'm sorry, I couldn't get the image to transfer. But I will keep trying.


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PostPosted: February 26, 2015, 8:10 pm 
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The point is,

I have a simple design which puts two valves, one each side of a pendulum. They are opened one at a time, depending on the direction of force and they open at an increasing rate depending on how far the pendulum pushes. This gives some flow control.

The fluids from each valve go into opposite ends of a dual-acting cylinder - push one way, push the other way. I just need some design work.


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PostPosted: March 26, 2015, 10:53 am 
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I suggest you need a feedback loop. Essentially that's how the driver works. He makes a turn, the car responds, he feels how the car responds and makes minor corrections to "fine tune" the car's subsequent response, and on and on.

You guys that race, if you had a co-driver that could alter the cars attitude while driving, how would you communicate with him/her to get what you wanted. This is called a feedback loop.


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